Problem: $2kl - 10km + 5k - 3 = -6l + 9$ Solve for $k$.
Answer: Combine constant terms on the right. $2kl - 10km + 5k - {3} = -6l + {9}$ $2kl - 10km + 5k = -6l + {12}$ Notice that all the terms on the left-hand side of the equation have $k$ in them. $2{k}l - 10{k}m + 5{k} = -6l + 12$ Factor out the $k$ ${k} \cdot \left( 2l - 10m + 5 \right) = -6l + 12$ Isolate the $k$ $k \cdot \left( {2l - 10m + 5} \right) = -6l + 12$ $k = \dfrac{ -6l + 12 }{ {2l - 10m + 5} }$